Synthesis of ethyl lactate in high yields with mesoporous SnSi mixed oxide catalysts prepared by the aerosol-assisted sol-gel process

An aerosol-assisted sol-gel method is used to prepare mesoporous tin silicate catalysts which exhibit record activity in the synthesis of ethyl lactate from dihydroxyacetone and ethanol. The method is based on the formation of an aerosol from a solution of precursors and surfactant. During the fast drying of the droplets, the surfactant self-assembles and the Sn-silica matrix is formed by polycondensation reactions. After calcination, the resulting material is composed of a true Sn-Si mixed oxide in the form of spherical microparticles with calibrated mesopores of 5-6 nm. Tin species are incorporated in the silica network, mainly in the form of single sites. The catalyst is shown to be recyclable and truly heterogeneous, as it can be reused for several cycles and as it does not leach